.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
.\"
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.\" manual under the conditions for verbatim copying, provided that the
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.\" %%%LICENSE_END
.\"
.\" References consulted:
.\"     Linux libc source code
.\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
.\"     386BSD man pages
.\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu)
.\" Modified 2002-07-27 by Walter Harms
.\" 	(walter.harms@informatik.uni-oldenburg.de)
.\"
.TH HYPOT 3 2021-03-22 ""  "Linux Programmer's Manual"
.SH NAME
hypot, hypotf, hypotl \- Euclidean distance function
.SH SYNOPSIS
.nf
.B #include <math.h>
.PP
.BI "double hypot(double " x ", double " y );
.BI "float hypotf(float " x ", float " y );
.BI "long double hypotl(long double " x ", long double " y );
.fi
.PP
Link with \fI\-lm\fP.
.PP
.RS -4
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.RE
.PP
.BR hypot ():
.nf
    _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
        || _XOPEN_SOURCE
        || /* Since glibc 2.19: */ _DEFAULT_SOURCE
        || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
.fi
.PP
.BR hypotf (),
.BR hypotl ():
.nf
    _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
        || /* Since glibc 2.19: */ _DEFAULT_SOURCE
        || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
.fi
.SH DESCRIPTION
These functions return
.RI sqrt( x * x + y * y ).
This is the length of the hypotenuse of a right-angled triangle
with sides of length
.I x
and
.IR y ,
or the distance of the point
.RI ( x , y )
from the origin.
.PP
The calculation is performed without undue overflow or underflow
during the intermediate steps of the calculation.
.\" e.g., hypot(DBL_MIN, DBL_MIN) does the right thing, as does, say
.\" hypot(DBL_MAX/2.0, DBL_MAX/2.0).
.SH RETURN VALUE
On success, these functions return the length of the hypotenuse of
a right-angled triangle
with sides of length
.I x
and
.IR y .
.PP
If
.I x
or
.I y
is an infinity,
positive infinity is returned.
.PP
If
.I x
or
.I y
is a NaN,
and the other argument is not an infinity,
a NaN is returned.
.PP
If the result overflows,
a range error occurs,
and the functions return
.BR HUGE_VAL ,
.BR HUGE_VALF ,
or
.BR HUGE_VALL ,
respectively.
.PP
If both arguments are subnormal, and the result is subnormal,
.\" Actually, could the result not be subnormal if both arguments
.\" are subnormal?  I think not -- mtk, Jul 2008
a range error occurs,
and the correct result is returned.
.SH ERRORS
See
.BR math_error (7)
for information on how to determine whether an error has occurred
when calling these functions.
.PP
The following errors can occur:
.TP
Range error: result overflow
.I errno
is set to
.BR ERANGE .
An overflow floating-point exception
.RB ( FE_OVERFLOW )
is raised.
.TP
Range error: result underflow
An underflow floating-point exception
.RB ( FE_UNDERFLOW )
is raised.
.IP
These functions do not set
.IR errno
for this case.
.\" This is intentional; see
.\" https://www.sourceware.org/bugzilla/show_bug.cgi?id=6795
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.ad l
.nh
.TS
allbox;
lbx lb lb
l l l.
Interface	Attribute	Value
T{
.BR hypot (),
.BR hypotf (),
.BR hypotl ()
T}	Thread safety	MT-Safe
.TE
.hy
.ad
.sp 1
.SH CONFORMING TO
C99, POSIX.1-2001, POSIX.1-2008.
.PP
The variant returning
.I double
also conforms to
SVr4, 4.3BSD.
.SH SEE ALSO
.BR cabs (3),
.BR sqrt (3)
.SH COLOPHON
This page is part of release 5.13 of the Linux
.I man-pages
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
\%https://www.kernel.org/doc/man\-pages/.
